At long last, the world’s largest mobile carrier by users, China Mobile, will start offering iPhones on its network after the company signed a deal with Apple.

The U.S. tech behemoth has been reluctant to use the Chinese carrier’s relatively unreliable 3G network, but as China Mobile goes 4G on Dec. 18, the iPhone is expected to be an integral part, the Wall Street Journal reports.

Gaining access to China Mobile’s 700 million subscribers could add almost 20 million additional iPhone activations in 2014, says research firm Trefis, representing a 17% increase from Apple’s handset sales in the fiscal year that ended Sept. 28.

Experiencing slowing revenue growth in the U.S., there is a major opportunity for Apple in China, a market where it has so far struggled amid competition from lower-cost rivals.